sex advice

I hooked up with this guy I really really like the other day, which was great! However, the sex was awful. Like the worst I've ever had. 
Part of that reason was because he is smaller than the other guys I've been with. He's fairly well endowed, just in comparison he felt tiny to me. 
Will that change as we have sex more and I get used to his size or is there something one or both of us can do to make it feel bigger?
I really like him so I don't want it to always feel like that for me. 
EDITED to add information 
Another reason it was so bad is he had stage fright which we were able to work through. It also caused me to be more assertive which I have a hard time with. So I'm grateful for that. 
I realize sex isn't the most important thing and in a way I'm glad it was bad because it helped me realize how much I actually like him. But when I like someone this much I don't want our sex life to be lackluster.